


Work of Constriction

by khrome



Category: Undertale (Video Game)
Genre: Bondage, Dom Papyrus, Ecto-Penis (Undertale), Edging, Established Relationship, Eventual Smut, Fontcest, M/M, NSFW, Overstimulation, PapySans, Sub Sans, Tentacles, handjob, muffet makes an appearence, papyrus learns a new trick, we like it when they wriggle, wriggling
Language: English
Status: Completed
Published: 2017-03-05
Updated: 2017-03-19
Packaged: 2018-09-28 10:33:04
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 3,377
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10093064
Author URL: https://archiveofourown.org/users/khrome/pseuds/khrome
Summary: Sans accidentally reveals a secret kink that Papyrus can't help but indulge in.





	1. Tight spot

**Author's Note:**

> Heyyy I'm back... Back with more dirt...  
> I'm sorry I didn't reply to any of the comments on my last fic... There was a lot of feedback and I got a bit overwhelmed. Sorry... I really like comments tho, so please don't be afraid to leave one. I'll try to reply to them sooner. 
> 
> This was inspired by a picture drawn by http://bones-n-boners.tumblr.com/ (warning: NSFW 18+ blog)  
> Since the picture has spoilers for this fic I'll put the link in the end notes.

Papyrus’ boots thumped quietly down the corridor, each footfall making a small slick noise from the webs cascading over the ground.

“TCH. I JUST SHINED THESE BOOTS!” Papyrus carefully made his way thought the increasingly mushy webbing, careful not to injure any spiders.

Papyrus was here in Hotland, trekking toward Muffets bakery, because his brother was late coming home… He had searched Sans’ usual sentry route but found nothing. Using his superior puzzle solving skills, Papyrus expertly deduced that Sans must have been neglecting his duties (again) and wandered off, perhaps getting lost outside of Snowdin.

A quick phone call confirmed just that.

* * *

 

_“SANS!!! I’VE CALLED YOU TWICE ALREADY!”_

_“yeah yeah i- *huff* i know paps, i couldn’t reach my phone… i’m at Muffets… uh, can you come get me? i’m a little tied up…”_

_“OH. WELL, I SUPPOSE I COULD SACRIFICE A LITTLE OF THE EVENING I HAD PLANNED FOR US… WHAT EVER WOULD YOU DO WITHOUT ME BROTHER?”_

_“heh. thanks paps, you’re the- *huhh* the coolest.”_

_“SANS. YOU SEEM WINDED. ARE YOU PERHAPS RUNNING TO MEET ME SOMEWHERE? DO NOT DO THAT. WHEN ONE IS LOST IT IS BEST TO WAIT IN ONE SPOT UNTIL ASSISTANCE ARRI-“_

_“*guh* paps no, i’m not- *hh* can you really see me runnin anywhere?”_

_“… NO, ACTUALLY. I DOUBT YOU COULD MOVE FASTER THAN A LIGHT SHUFFLE REALLY…”_

_“ouch. your words cut me deep.*heh*  i can feel my blood *ghh* runnin outta my body…”_

_“SANS THIS IS NO TIME FOR TERRIBLE ANATOMICALLY INCORRRECT WORDPLAY. I’M ON MY WAY.”_

* * *

Papyrus looked up from his feet and found himself at Muffet’s Bakery, said monster happily pouring herself a cup of (spider??) tea.

“Ohoho? Hello dearie! Are you here for the spider bake sale?” Muffet motioned to the table of pastries in front of her, cheerily blinking her eight slender eyes.

“HELLO MISS MUFFET. I’M AFRAID NOT, I’M HERE LOOKING FOR SOMEONE-“

“Another skeleton?”

“WHY YES! MY BROTHER. DID HE PASS THROUGH HERE?”

“Fuhuhuhu!!! I’m afraid he didn’t pass through…” Muffet smirked.

Papyrus tilted his head in confusion. “BUT I THOUGHT YOU SAI-“

“He never left! You have to buy something to pass through my shop… He didn’t pay up so I had my spiders put him in time out! Fuhuhu!”

“TIME OUT?” Papyrus turned around in a sloppily executed circle, looking in all the corners for his brother.

“WELL THEN WHERE-“ Papyrus was interrupted by the clanking of a teacup.

Muffet strutted out from behind her table, using three arms to point out into the darkness over the edge of her walkway of webbing. Down below, on a second floor of spider-filled web, sat a little capsule with a familiar skull poking out.

“He said if I allowed him a phone call someone would bring me what he owed!”

Papyrus’ stare of relief at seeing his brother quickly changed to annoyance. Turning to Muffet he was greeted by two open palms and a pleasant smile.

“50G deary! Hehe!”

“AH. YES. THE GREAT PAPYRUS WILL GLADLY COMPHENSATE YOU FOR YOUR TROUBLE WITH MY BROTHER! MY APALOGIES FOR HIS DISTURBANCE.”

“No trouble at all dearie! I was going to feed him to my pet for making jokes at the expense of spiders, but this was a much better turn out!”

Papyrus blanched at the thought. How unfortunate it would be if his brother and soulmate were to be gobbled up by a giant muffin with teeth…

“Y-YES INDEED. I MUCH PREFER THIS OUTCOME. UHM. DO NOT HESITATE TO CALL ME IF HE HAPPENS TO WANDER THROUGH AGAIN. PLEASE.”

“Ohohho! Anything for 50G my dear!”

Handing Muffet her payment and being careful not to land on any spiders, Papyrus lowered himself down to the second level, slowly making a sticky path toward Sans.  
Once he was out of earshot, Papyrus glared down at the cocooned skeleton in front of him. Sans was asleep, phone stuck to one side of his face. These webs will take forever to get off his bones!

“SANS. WAKE UP LAZYBONES! THE MAGNIFICENT AND MERCIFUL PAPYRUS IS HERE TO RESCUE YOU FROM YOUR INEVITABLY CRUMBY DEMISE!”

Sans woke with a small start, jolting the web surrounding him. His skull faded blue as he glanced up toward Papyrus, his breathing coming out in shallow breathes.

“oh hey paps. *guh* how’s it hangin?” Sans’ eyelights nervously trailed to the side.

“SANS! SPARE ME YOUR TOMFOOLERY! I HAD A PLEASANT DATE PLANNED OUT FOR US AT HOME BUT NOW WE ARE BOTH MORE THAN AN HOUR LATE! TO BOTH OUR DATES! WITH EACHOTHER! DO YOU KNOW HOW IMPOLITE WE ARE BEING RIGHT NOW?”

“sorry paps. seems i’m- *huff* in a bit of a bind… lemme make it up to ya? right after i- *hhf* just lemme- *hh* um..”

Sans began to sweat from attempting to twist his bones out of the tight webs. Curious spiders began to crawl toward the disturbance in the web.

“SANS, IT NO USE. LET ME TRY AND-“

“no! *hhu* no… uh. i can get it. just need to- *guh* why is it so sticky?!” Sans slumped in his bonds, looking quiet exhausted, his breathing still shallow, his skull blushing darker by the second, sweat trailing over his bones… Papyrus entertained the thought that his brother looked rather nice this way.

“PERHAPS YOU HAVE FORGOTTEN BROTHER! I AM A MASTER OF TRAPS AND PUZZLES! I KNOW THE PERFECT WAY TO SET YOU FREE!” Papyrus flashed a grin at Sans, striking a pose as he summoned a small bone weapon with one end sharpened to a small point.

“THESE WEBS ARE NO MATCH FOR MY SUPERIOR BONE MAGIC! NOW. WATCH YOUR PHALANGES…”

Sans stiffened. Leaning his head away from the small point as Papyrus began neatly slicing down the wall of webbing that encircled his brother.

“wow paps. you’re so cool. i definitely couldn’t have done that by myself… uh, you can stop now, i’ll just step out of the bottom..” Sans attempted to lift his legs out of the sticky string, still stuck from the waist down.

“NONSENSE! YOU’LL JUST TRIP AND FALL OVER AND GET TRAPPED AGAIN!” Papyrus knelt down and continued slicing. “STOP MOVING! JUST LET ME-“

“no really, i’ve got it.” Sans’ blue blush returned. “paps just-“

“THERE WE ARE!” Papyrus grinned triumphantly, brushing the webs off of Sans’ shorts.

“NOW TRY AND LIFT YOUR… YOUR… MASSIVE ERECTION??” Papyrus blinked in surprise; right in front of him, standing to attention, was the familiar sight of Sans’ magic formed into a blue ecto-cock, straining at the fabric of his shorts.

The eyelights of Sans’ sockets went out. Skull bathed in blue, Sans quickly and clumsily pulled his feet from the remains of the webs. He turned from Papyrus’ blank expression and tugged his hoodie down over his shorts.

“ok  i’m free now let’s go home i think the spaghettis getting cold right? i could go for some spaghetti to forgetti my regretti if ya don’t mind so let’s get a move on ok?” Sans mumbled the half-hearted line of conversation as Papyrus steadily got to his feet.

The sweat on Sans’ skull was practically pouring off of him now. He drew his hood up, avoiding Papyrus’ calculating gaze.

“… YES… WELL. WE CERTAINLY DON’T WANT COLD SPAGHETTI…” Papyrus followed his brother’s light shuffle out of Muffets bakery and into Hotland.

 

* * *

 

The walk home was awkward to say the least.

Papyrus politely made conversation; informing Sans about the state of his culinary training with Undyne, and reporting on the new puzzles he had been building around the forest. Sans only responded with the occasional hum or “that’s neat paps” without ever adding to the conversation.

Papyrus mulled it over in his skull.

Sans was clearly aroused back there, tightly bound by strings… Why was he so embarrassed? Surely Sans’ knew that Papyrus was more than willing to indulge in… _those_ type of things… Papyrus had more than a few bedroom fantasies he wanted to try out. Maybe, Papyrus thought, he could make a change to some of his evening plans…

Dinner proceeded like normal; Sans had an opportunity to calm down and Papyrus used his loving charm to settle Sans into the date. The whole dinner was filled with laughter and puns and much talk about each other’s day. Dates like these were not meant to be super extravagant, despite Papyrus’ overzealous nature; ever since they confessed to each other, spending time like this was always a quiet comfortable moment.

Papyrus watched Sans push spaghetti around on his plate; today must still be on his mind.

Not that Papyrus was thinking about it. Not at all… Well, maybe a little.

Just enough to come up with a plan for the evening to progress.


	2. Tighter spot

**Summary for the Chapter:**

> Papyrus takes the initiative. He has captured Sans... Now what to do with him?

**Notes for the Chapter:**

> Hey guys! I'm sorry this took much longer than expected. I hope you like it!  
> I love comments, and kudos are much appreciated!  
> Enjoy!

 

“SANS!” Papyrus called from the kitchen while holding a newly cleaned pan.

“yeah bro?” Sans casually strolled into the kitchen, leaning against the counter. “anything i _pan_ do for you?”

Papyrus ignored the pun, twitching an eye socket, then flashing a toothy grin toward the smaller skeleton.

“YES ACTUALLY. I NEED YOU TO PUT THIS PAN IN THE BOTTOM DRAWER.”

“down there?”

“YES.”

“… are your knees okay bro?”

“SANS WOULD IT KILL YOU TO HELP OUT EVERY ONCE AND A WHILE?”

“ _patella_ the truth i’d rather be nappin. but i’ll help ya out bro.” Sans chuckled.

Taking the dish from Papyrus, he bent down to slid it into the cabinet drawer. Suddenly, a firm pressure was down on his spine.

Sans went still.

Papyrus’ hand splayed out on his upper spine, keeping him from standing up straight. The gentle pressure rubbed up and down, massaging his vertebrae.

“p-paps? you… n-need somethin?” Sans shivered. He had been trying to convince Papyrus to fuck in the kitchen for months. Was this really happening. Oh hell yes.

“RIGHT AGAIN SANS… I DO NEED SOMETHING. I NEED IT… VERY BADLY.”

Papyrus leaned forward, sliding his hand up Sans’ spine to grip at his neck vertebrae. Papyrus pressed his pelvis into the back of Sans’ shorts, feeling a shiver run through the flustered skeleton below him.

“p-ahh… papyrusss...” Gripping the counter in front of him, Sans rocked back into his lover, his knees felt weak, sweat began to collect on his skull.

“OH SANS…” Papyrus growled out in a low tone. “I NOTICED SOMETHING NEW ABOUT YOU TODAY… DO YOU WANT TO KNOW WHAT IT WAS?” He questioned while moving a hand underneath his brother’s shirt, stroking and pulling at his ribs.

“aahh… t-tell me b-b- nnn! bro…”

“I SAW HOW MUCH YOU LIKED BEING TIED UP AT MUFFETS.”

Sans stiffened.

“SANS… IF YOU WANTED TO… EXPERIMENT… IN THE BEDROOM, YOU COULD HAVE TOLD ME… I’M ALWAYS UP FOR NEW THINGS…”

“i… i uh… paps…”

“WOULD YOU LIKE THAT?” Papyrus tightened his grip on Sans’ ribs, using the other hand to squeeze around his trembling form.

“TIED UP NICE AND TIGHT, COMPLETELY AT MY MERCY, ENJOYING ALL THE ATTENTION I GIVE YOU. HOT. BREATHLESS-”

Sans panted, a high-pitched whine slipping through his teeth. Blue light shone softly from underneath his shorts, his magic had built up into the form of a deep blue ecto-cock, shorter than Papyrus’ own member, but thicker. Papyrus hummed with approval. This was perfect.

“pahh… please… it’s *hah* embarrassing…”

“NO NEED TO BE EMBARASSED SANS. IT’S SOMETIMES HARD TO CONTROL ONE’S MAGIC WHEN IN A STATE OF AROUSAL.” Sans’ breath hitched as papyrus pulled him up into a standing position, lanky arms around his chest holding him slightly off the ground. Sans’ feet kicked lazily in the air as Papyrus began walking out of the kitchen.

“I, ON THE OTHER HAND, AM THE GREAT PAPYRUS- I HAVE SUPREME CONTROL OVER MY MAGIC. IN FACT, I’D LIKE TO SHOW YOU JUST HOW MUCH CONTROL I CAN HAVE OVER YOU, BROTHER…”

Sans chuckled, craning his skull up to look at Pap’s face. Oh, he looked so excited- cheekbones dusted with pale orange, a glint in his eye sockets, tombstone teeth grinning to his ear-holes. Sans couldn’t imagine saying no to that face.

“of course paps… i’m yours…”

At the top of the stair, Papyrus turned sharply toward the room where he slept, carefully closing the door with his boot, then safely depositing a disheveled Sans onto his bed.

* * *

 

 

With every piece of clothing removed, more and more pearly white bones were revealed to the open air. Sans inhaled a breath when his shorts hit the floor. Papyrus remained fully clothed, part of his plan to spoil Sans, giving him every amount of focus he could muster.

Carefully placed touches along Sans’ spine, his ribs, the cartilage between each individual bone, the expanse of his femurs and humerus- his hands were everywhere except the one place Sans’ wanted them to be.

Papyrus relished in the sight before him- Sans eye lights were blown wide, bones glowing blue with excited magic, his phalanges shakily curled around Papyrus’ arms to steady himself, Sans hips pressed forward in broken rhythm, trying to get any sort of stimulation.

“wh-wh-haaahh! why are y-you t-teeease- ah!” Sans shuddered as the younger suddenly attacked his neck, running that mischievous orange ecto-tongue over his vertebrae and collar bones. Sans felt his magic strain- pulsing with pent up energy. Pretty unusual for such a lazybones…

“MM… SANS… T-TELL ME WHAT YOU… HMM… WHAT DO YOU WANT SANS?”

“stars paps touch me please. p-please just anything i need it papy i… haahh… i w-want you in… inside… paahhp!!”

“DO YOU WANT ME TO… RESTRAIN YOU? SANS?” Papyrus purred. “AFTER ALL… YOU ARE MOVING QUITE A BIT…”

Sans arched into his lover’s touches, barely concealing his excitement over this new territory. They had never done anything particularly extra in the bedroom… Sans knew he would have never suggested it himself, but Papyrus’ enthusiasm won him over. Whenever Papyrus took control Sans practically melted into a writhing pile of bones and sweat.

“yes yes yes!!! stars yes, pap…”

No sooner had Sans uttered those words, then Papyrus lifted Sans from underneath him. Now sitting upright, Sans straddling Papyrus’ lap.

The final piece of the puzzle was about to fall into place.

Papyrus’ right eye socket lit up with his warm magic, a single pupil manifesting and blazing a trail of orange. Sans noticed, and smiled encouragingly at his younger brother. Papyrus returned the gaze with a dangerous look- almost predatory in nature.

Sans felt something slide up around his elbow… And another something slither up his lumbar vertebrae… And another on his tibia… Wait, what?

“uh- wha- paps what is that? what are you d-” Sharply turning his skull, Sans saw around five or six bright orange tentacles making their way from behind Papyrus all the way up Sans’ tiny body.

They tingled on his bones as they began to wrap around his ribcage, his neck, his spine… One came down to rest between his femurs, slowly running back and forth over his iliac crests, rubbing up against his cock and the entrance beneath it.

“hhhhh-!! oooooh… hnn! pap!” Sans felt his breathing pick up as the tentacles kept their winding pace till he was completely covered in orange- his arms pinned to his sides, his legs folded up neatly beneath him- completely bound. The only part not wrapped up in Papyrus’ magic was his skull and his blue cock; weeping precum and so stiff it was uncomfortable.

Papyrus shifted Sans around, cradling his cocooned brother in his lap. Like a tiny, horny package of bones.

“I TOLD YOU I HAVE MAGNIFICENT MAGIC CONTROL.” Papyrus leaned down to run his tongue over Sans teeth, successfully gaining entry and ravaging his mouth in a deep kiss. Pulling away to look at his brothers flustered skull.

“HM… YOU LOOK LOVELY LIKE THIS BROTHER.” Papyrus hovered a hand over Sans’ pelvis.

Sans attempted to push his hips upward, but found all he could do was flop uselessly in his brother’s arms. He had no control at all, he was completely at his brother’s mercy… Sans felt so hot, magic burning in his bones as he continued to weakly struggle.

“oh s-stars pap this is so f-fucking hot p-please stop teasing me bro… i’m c-caught up in the moment… heh. heheh-ah!”

Papyrus narrowed his sockets at the pun before flaring his magic once more- the tentacles positioned under the others, right next to Sans’ entrance began to press inward, rubbing at the tight ring of magic, smearing orange liquid in preparation.

“haa!! p-papyrus!!! uuhngg-!”

Papyrus wrapped his hand around Sans’ dick and tugged once, twice- three times before stopping.

“WATCH YOUR MOUTH BROTHER. FILTHY LANGUAGE AND DIRTY PUNS WILL NOT BE TOLERATED. YOU’RE IN _MY_ WEB NOW… NYEHEH.”

The tentacle down near Sans’ magic pressed forward more insistently, carefully stretching Sans.

This continues for a few minutes; Papyrus was kissing him, gently tugging at Sans’ cock, pressing into his entrance more and more till it burned with stimulation. Sans tried to move- to thrust, to reciprocate, anything to get this moving faster!

The tentacle finally entered Sans completely, resting there for a moment to let Sans adjust before shallowly thrusting in and out. Papyrus nibbled on Sans exposed neck vertebrae and sped up his hand on Sans leaking cock.

“t-this certainly is a- hah! hnn… a ‘sticky’ s-situation…”

“REALLY SANS?”

“heh… in m-more ways than one…”

“SANS PLEASE.”

“c’mon b-bro… heh… you’ve got me _wrapped_ around your finger…”

“YOU ARE ENTIRELY TOO COHERENT RIGHT NOW.” Papyrus tried to hide his smile with a scowl.

“DON’T WORRY SANS. THIS CAN BE REMEDIED…”

All at once Papyrus sped up his assault on a helpless Sans; pushing the tentacles in and out of Sans faster and faster, rubbing his hand up and down Sans’ length, rubbing the tip and smoothing pre-cum over the head.

“fff-! aah! ah! haaahh~” Sans moaned lecherously into the air. He felt so full- he couldn’t move, could hardly breath from how much pleasure was washing over him. He felt the tendril grow inside him, filling him up even more and going so deep-

“gahhhn!! s-stars papyrus!!! yes yes y-yesss p-please papy i n-need more- ah! haah!”

Immediately a tentacle came up toward Sans cock and curled around the length of it, imitating a warm wet passage going up and down, loud squelching noises filled the room. The tendril inside Sans bottomed out with every thrust, then changed angles to press against that sweet spot deep inside-

Sans let out a wet cry, tears falling from his sockets. He was practically screaming from every thrust as the rhythmic pleasure engulfing him. Calling out papyrus’ name like it was the only word he knew how to say. He was so close- so close- just a little more-!

Papyrus felt a deep sense of satisfaction at seeing his brother crumble into a convulsing mess as his climax hit him. Sans spilt cum all over Papyrus’ hand, his cock pulsing and twitching with every stream. His magic clenched around the tentacle now stilled inside him. Sans eye lights shaped into tiny little hearts and rolled to the back of his skull, tears falling toward his mouth which was strung up in a shaky grin.

Papyrus gave sans a moment to come down from his high; the small skeleton sighed and panted as the tremors of his orgasm faded out. Yet the tentacle bondage did not dissipate.

“haaah…. mmn… papyrus…? you can *hah* untie me now…”

“OH SANS. MY BEAUTIFUL SANS…” Papyrus nuzzled against the others skull with his teeth.

“I’M NOT FINISHED WITH YOU YET, DEAR BROTHER…”

Sans’ soul thumped in his chest, feeling his magic begin to react once more…

* * *

 

 

Four intense orgasms later, Sans was passed out on Papyrus’ chest; limbs splayed out across the sheets while he slept deeply. Papyrus looked down upon his lover with fondness. This new activity seemed to be a humongous success. Of course, Papyrus would except nothing less than greatness in all his endeavors. After untying Sans and cleaning his sweaty bones with a washcloth, Sans had offered to reciprocate but… He would probably have to wait until he could feel his legs again. Perhaps next time, there would be something else they could try…

Pulling closer to Sans and guiding the bedsheets up over both, the Great Papyrus decided a nap was in order before planning his new ideas.

**Notes for the Chapter:**

> This work is inspired by this picture drawn by bones-n-boners (NSFW 18+) on Tumblr:  
> http://bones-n-boners.tumblr.com/post/146619280289/commission-done-for-everythingunderwraps-sans
> 
> Follow me on tumblr! >>> https://bigbitchbot.tumblr.com/  
> Or, check out another fic of mine featuring Underswap fontcest: "Work of Friction" http://archiveofourown.org/works/6641734

**Author's Note:**

> The pic--> http://bones-n-boners.tumblr.com/post/146619280289/commission-done-for-everythingunderwraps-sans
> 
> If you want to find me I'm on tumblr at http://bigbitchbot.tumblr.com/


End file.
